OVERALL SUMMARY Despite major progress, malaria remains a major public health burden in India. The number of cases has declined in many regions, but reservoirs persist through untreated asymptomatic and subpatent infections that together contribute to resurgence of the disease in the post-monsoon season. This proposal outlines two independent but complementary projects in two geographically distinct but highly malarious Indian states: Odisha and Meghalaya. Both are hilly, forested states with predominant indigenous (tribal) populations and inaccessible, remote pockets where the burden of malaria is most evident. The long-term goal of this work is to evaluate the current use and implementation of malaria control strategies provided by the state governments, and importantly to improve and inform intervention uptake and efficacy. In Meghalaya, a socio-behavioral Study Type 2 project will be conducted in Nonglang PHC (primary health center) in the district of West Khasi Hills, and Barato PHC in the district of Jaintia Hills, the sites of ongoing parent grant epidemiology studies, to evaluate the use, misuse, attitudes, opinions, and uptake of IRS (indoor residual spraying) and LLINs (long-lasting insecticide treated nets) used for malaria control. The study is purely observational and will consist of FGDs (focus group discussions) with small groups of villagers, and individual interviews with key figures within each village. The study aims to identify what interventions the villagers use, why some are used and not others, and where and how they are being used. Additionally, social network analysis will be applied to map the influence structure in each village to determine how we can best improve IRS and LLIN uptake at the individual village level. Study findings will inform malaria control and intervention strategies in Meghalaya as well as inform the Study Type 3 project in Odisha. Specifically, the knowledge gained from the FGDs in Meghalaya will guide the FGDs in Odisha and provide insights on how to improve uptake of existing interventions across state borders. In Odisha, a Study Type 3 project will conduct a hybrid cluster randomized implementation trial to evaluate the effectiveness of malaria camps (MCs) in reducing malaria cases as detected by PCR relative to standard intervention practices, with the overall goal of determining intervention efficacy and informing Odisha state government. MCs were recently introduced by the state Malaria Control Program and utilize screening and treatment of individuals in combination with intensified vector control and malaria educational activities. Relative to standard interventions provided by the state (e.g. LLINs, IRS), the study aims to evaluate the utility of MCs in collaboration with the state government to best guide downstream control efforts. Molecular biology, host immunology, genomics, mathematical modeling, global information systems, and cost-effectiveness analysis will be used to achieve the objectives.